These swifts are found across most of Europe, Asia, and Africa. Their diet consists entirely of insects they catch in the air. Apart from nesting, Common Swifts spend most of their time flying. They catch food, skim water sources to drink, and even sleep in flight, spending more of their life in the air than almost any other bird. Common Swifts build nests from feathers and plant materials held together by saliva. Pairs stay together for several years and return to the same nesting colony each May. Despite their similar appearance to swallows and martins, swifts are not closely related to these species. The similarities are due to convergent evolution.